Chemistry

• the study of matter, its composition, properties, and transformations.
• Anything that has mass and takes up volume

• Solid
• Liquid
• Gas

• Has a definite volume
• maintains its shape regardless of its container
• has particles that lie close together in a regular 3-D array

• Has definite volume
• takes the shape of its container
• has particles that are close together but can move past one another

• Has no definite shape or volume
• Expands to fill the volume and assumes the shape of whatever container it is put in
• Has particles that are very far apart and move around randomly

Properties: can be observed or measured without changing the composition of the material;

Change: alters the material without changing the composition.

ex. melting point, boiling point, solubility, color, odor

Properties: determine how a substance can be converted into another substance

Change: the chemical reaction that converts one substance into another

ex. piece of burning paper, metabolizing an apple for energy, oxygen and hydrogen combining to form water

• composed of a single component
• has constant composition regardless of sample size and origin of sample
• Cannot be broken down to other pure substance by a physical change

ex. table sugar (C12H22O11), water (H2O)

• is composed of more than one component
• can have varying composition (any combination of solid, liquid, and gas) depending on the sample
• can be separated into its components by a physical change
• ex. sugar dissolved in water=mixture

A pure substance that cannot be broken down by a chemical change

ex. aluminum

A pure substance formed by chemically joining two or more elements

• Length = meter
• Mass = grams
• Volume = liter

• Exact numbers - have no uncertainty associated with them
• Inexact number - result from a measurement or observation and contains some uncertainty

• 1) All non zero numbers are significant
• 2) A zero counts as a sig/fig when it occurs:
• a) between two nonzero digits
• 29.05 (4 sigfig) 1.0087 (5 sigfig)
• b) at the end of a number with a decimal place
• 3.7500 (5 sigfig) 620. (3 sigfig) 620 (2 sigfig)
• 3) A zero does not count:
• a) at the beginning of a number
• 0.00245 (3) 0.008 (1 sigfig)
• b) at the end of a number that does not have a decimal
• 2570 (3) 1245500 (5 sigfig)

The answer has to have the same number of sig figs as the original number with the fewest significan figures

• 351. 2 miles = 63.854545 miles
• 5.5 hours hour

63 miles per hour

The answer has the same number of decimal places as the original number with the fewest decimal places.

• 10.11 2 decimal places
• - 3.6 1 decimal place
• 6.51 answer must have 1 decimal place = 6.5

• When the exponent x is positive. move the decimal point to the right.
• 2.800 X 10²= 280.0
• When the exponent is negative, move the decimal to the left.
• 2.80 X 10^-2= 0.0280

• 1) Identify the original quantity and the desired quantity including units.
• 2) Write out hte conversion factor needed to solve the problem.
• 3)Set up and Solve the problem

Ex. How many grams of Asprin are in a 325mg tablet?

• 1) Original quantity - 325 mg Desired quantity - ? g
• 2)1g = 1000mg
• 3) 325mg X 1g = 0.325g
• 1000mg

• The measure of the kinectic energy of a collection of object.
• Kelvin, Farenheit, Celsuis

• C --> F
• F = 1.8(C) + 32

• F --> C
• C = F - 32
• 1.8

• C ---> K
• K = C + 273

• K ---> C
• C = K - 273

• Density = Mass
• Volume

a characteristic physical property that relates the mass of a substance to its volume and has a specific value

A quantity that compares the density of a substance with the density of water at the same temperature

• Specific gravity = density of a substance (g/ml)
• density of water (g/ml)
• contains no units

Accuracy - the degree of agreement between the true value and the measured value

Precision - a measure of the aggreemnent of a replicate measurements